1. Technical Field of the Invention
The invention relates to an implant for attaching a bone cover or bone fragment, and more particularly for fixing a bone cover or a skull bone fragment removed in a craniotomy to a skull cap. The invention also relates to a device for securing the said implant to the bone cover or bone fragment.
2. Description of the Prior Art
Within the framework of skull operations, bone covers, i.e. plate-shaped bone parts, are often sawn out of the skull bone. At the end of the operation, it is necessary to fix these bone covers again in the resulting opening in the top of the skull, so that the bone cover can heal into its old position again. A comparable problem arises when skull bone fragments need to be fixed in the region of the top of the skull.
Various implants have been proposed for attaching bone covers or skull bone fragments. Thus, implants are known which comprise two screw holes. In a first step, implants of this type are secured by means of screws to the bone cover, for example, which is to be fixed in place. Subsequently, the implants screwed to the bone cover are additionally securely screwed to the skull bone. As a result of the fact that it is firstly necessary to secure each individual implant by means of a screw in each case to the bone cover and then to the skull bone, the fixing of the bone cover is very time-consuming. In order to reduce the time outlay associated with the fixing of a bone cover, self-retaining implants have been proposed.
A self-retaining implant of this type is known, for example, from DE 199 07 354 A1. This implant is a clamp-like element, which is placed onto the bone cover which is to be fixed. To this end, the implant comprises two contact arms, which are arranged spaced apart from one another and in the fitted state of the implant engage around the bone cover. In this respect, the first of the two contact arms contacts the upper side of the bone cover and the second of the two contact arms contacts the underside.
A disadvantage in a clamp-like implant of this type is that it is awkward to handle. The awkward handling is first and foremost a result of the fact that different bone covers are not always of the same thickness and the thickness of a single bone cover may even vary. A further disadvantage is that the contact arm resting against the underside of the bone cover rests upon the flaps of the meninges once the bone cover is secured and under certain circumstances may damage the flaps.
It is the object of the invention to provide an implant system which comprises a self-retaining implant offering simplified handling.